Method and means for forming metallic bellows



1113- 1 1937- E. c STANLEY 12,068,086

METHOP AND MEANS FOR FORMING METALLIC BELLOWS Filed July 30., 1932 2 Sheets-Sheet l INVENTOR 15 13 13 Edgar C. Stanley Jan. 19, 1937. STANLEY 2,068,086

METHOD AND MEANS FOR FORMING METALLIC BELLOWS Filed'July 30, 1932 2 Sheets-Sheet 2 INVENTOR Edgar C. Stanley Fatented Jan. 19, 1937 UNITED PATENT OFFICE METHOD AND MEANS FOR FORlVlING METALLIC BELLOWS Application July so, 1932, Serial No. 626,323

17 Claims.

This invention relates to a method and means for forming circumferentially corrugated tubes or bellows. The method and apparatus here described is particularly applicable to tubes formed of steel, or of material having substantially the characteristics of steel.

A method heretofore employed for forming a circumferentially corrugated tube consisted in pressing the wall of the tube between a pair of externally-tangential dies which therefore engaged the wall at substantially'a point, and then providing for relative rotation between the tube and the pair of dies. While this method Was found suitable for tubes formed of copper, or material having substantially the characteristics of copper, it was unsatisfactory in the case of steel tubes or tubes formed of material having substantially the characteristics of steel. In the case of tubes made of steel or similar material any attempt to form circumferential corrugations by the method employed in the case of copper tubes resulted in crimping and breaking of the relatively thin metal.

Moreover, the method heretofore employed consisted in stretching the material of the tube over the die which determined the shape of the corrugations, the stretching of the material causing thinning and corresponding weakening of the tube.

It is the principal object of my invention to provide a method and apparatus for forming circumferential corrugations in relatively thin tubes which will be capable of forming a plurality of relatively-deep axially-flexible corrugationsin tubes of steel, and of other material having the characteristicsof steel as to hardness, ductility, etc., without crimping and without causing undue thinning out and consequent weakening of the material.

Further objects and advantages of this invention will become apparent in the following detailed description thereof.

In the accompanying drawings,

Fig. l is a plan View, partly sectioned horizontally, showing my method and apparatus.

Fig. 2 is a section taken on the line 2-2 of Fig. 1.

Fig. 3 is a view similar to Fig. 1 but showing a modified form of my invention.

Fig. 4 is a view similar to Fig. 1 showing another form of my invention.-

Fig. 5 is a view similar to Fig. 1 showing a further form of my invention.

Fig. 6 is a view of a completed corrugated tube, with part broken away.

Fig. 7 is a view similar to Fig. 1 but showing the method heretofore employed.

Fig. 8 is a. view similar to Fig. 1, showing still another form of my invention.

Fig. 9 is a view similar to Fig. 2, taken on the line 99 of Figure 8.

Referring first to Fig. 7, there is illustrated a method heretofore employed for forming circumferential corrugations in tubes. By this method, a mandrel IIi was inserted within the tube II and mounted for rotation in a lathe between head-stock H and tail-stock T. Said mandrel carried one element I2 of a pair of dies, the other die I3 being carried by the tool-rest R. It will be seen that the inner and outer dies make substantially point-contact with the tube by reason of being externally tangential to each other, so that as the inner mandrel is rotated, point-contact is made successively around the circumference of the tube. Such point-contact results in crimping, in the case of steel tubes or tubes made of material having substantially the characteristics of steel. Also, it will be seen that as die I3 presses the tube over die I2, the material may be unduly stretched, with consequent thinning and weakening. By my method of forming corrugations} avoid both of these objections to the method now in use.

Referring to Figs. 1 and 2 I have shown an inner mandrel I0 within tube II, said mandrel being mountedin the lathe for rotation. One of the essential elements of my invention whereby I am enabled to overcome the hereinbefore mentioned objections to the method now in use is disclosed in Figs. land 2 in the die I3. While the mandrel Illf carries a die member I2, similar to member I2 carried by mandrel Ill, I avoid point-contact by employing a die I3 of arcuate construction arranged so that dies I2 and I3 are internally tangential, instead of employing two rollers, such as dies I2 and I3 externally tangential. The are of die I3 is of substantially the same radius as tube I l and engages around the tube throughout an are substantially greater than that necessary to provide point contact. In fact contact may be effected throughout an arc substantially equal to' a semi-circle, and thus I obtain line contact instead of point-contact between die I 3' and tube II. The mandrel is sufficientl'y smaller than the tube to permit withdrawal of the mandrel and its die member I2 after the shallow corrugation I4 has been made. It will be understood that a pair of die members I3 are applied on either side of die I2 so as to form the shallow corrugations I4 as the first step in forming the corrugations. By providing line-contact in place of point-contact heretofore employed, I have found that crimping is avoided regardless of the type of material of which the tube is formed. Steel tubes may be corrugated as readily as copper tubes. The stationary outer dies provide the necessary drag effeet, and the friction which would ordinarily be created by such effect is reduced by the use of a lubricant.

When the initial corrugations M have been formed in tube l I, the mandrel I0 is replaced by a mandrel H1" having a narrower die member l2, to permit the corrugations [4 to be carried deeper and brought closer together. This requires also another set of die-members, similar to l3 but of greater degree of curvature and positioned closer together, to be set up in the toolrest. As an alternative to providing successive sets of dies I3, each set having the members closer together, I may provide for continuous operation of a single set of die members l3", as shown in Fig. 3. Here inclined guides 20 are provided, and the members [3" are operated along said inclines by suitable means such as rack 2i on the dies coacting with pinion 22 on a shaft 23 journaled in the tool rest it and operated by handle 24, to bring the members 13 closer together as the handle is operated. In the final form the tube is as shown in Fig. 6.

The action as above described consists in bringing the ends of the tube more closely together as a result of folding the material over the dies l2, I2, instead of stretching the material.

In the forms of invention shown in Figs. 4 and 5, I can avoid the necessity of providing successive mandrels, each with a progressively narrower die member !2. Thus, in the Fig. 4 form I fill the tube with a fluid such as oil, sealing the ends by closures ET. The fluid within the tube thus forms in effect an infinitely adjustable die of a radius equal to the internal radius of the corrugation, and will permit the tube to take any form given to it by the die members l3.

In the Fig. 5 form I accomplish the same result by coating the mandrel with a layer of rubber l8 whose yielding quality gives the same infinitely adjustable inner die as the fluid in the Fig. 4 form; i. e., the inner die is always of the same radius as the internal radius of the corrugation.

In the Figs. 8 and 9 form of the invention I utilize an inner die member l2a. having the same radius as the inside of the tube, so that both inner and outer die members conform to the curvature of the tube along a substantial arc of contact. I am enabled to use such an inner die by reason of the fact that said die is less than semi-circumferential so as to permit its withdrawal after a corrugation has been formed. As the depth of the corrugation increases, successive dies l2a making contact with shorter arcs of the tube are employed. Each die l2a may be formed integral with a shaft Illa fixed at one end in the tail stock T and bearing at its other end in the head stock H. The tube ll may be supported on an inner cylinder [9 carried by the head stock, the shaft Illa. extending through an opening in said cylinder.

In accordance with the provisions of the. patent statutes, I have herein described the principle and operation of my invention, together with the apparatus which I now consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention can be carried out by other means. Also, while it is designed to use the various features and elements in the combination and relations described, some of these may be altered and others omitted without interfering with the more general results outlined, and the invention extends to such use.

Having now described my invention, what I claim and desire to secure by Letters Patent is:

1. In a device for forming circumferentiallyclosed corrugations in a tube, inner and outer die members for cooperating with said tube, one of said die members being so formed as to engage said tube along an elongated circumferential arc thereof, and means for rotating said tube, one of said die members being non-rotatable and said other die member being rotatable.

2. In a device for forming circumferentiallyclosed corrugations in a tube, inner and outer die members for cooperating with said tube, said outer die member being so formed as to engage said tube along an elongated circumferential arc thereof, and means for rotating said tube, said outer die member being non-rotatable and said inner die member being rotatable.

3. In a device for forming circumferentiallyclosed corrugations in a tube, inner and outer die members for cooperating with said tube, said die members being so formed as to engage said tube along an elongated circumferential arc thereof, and means for rotating said tube, one of said die members being non-rotatable and said other die member being rotatable.

4. In a device for forming circumferential corrugations in a tube, inner and outer die members for cooperating with said tube, one of said die members being so formed as to engage said tube around an are substantially equal to a semi-circle, and means for relatively rotating said tube and said last-named die member, one of said die members being rotatable.

5. In a device for forming substantially-parallel circumferential corrugations in a tube, inner and outer die members for cooperating with said tube, said tube and die members being internally tangential, one of said die members being of substantially the same radius as said tube, and means for relatively rotating said tube and die members, one of said die members being rotated.

6. In a device for forming circumferential corrugations in a tube, inner and outer die members for cooperating with said tube, said tube and die members being internally tangential, one of said die members being of substantially the same radius as said tube and engaging said tube around an are substantially equal to a semi-circle, and means for relatively rotating said tube and die members, said inner die member being rotatable.

7. In a device for forming substantially-parallel circumferential corrugations in a tube, inner and outer die members for cooperating with said tube, said tube and die members being internally tangential, said outer die member being of substantially the same radius as said tube, and means for relatively rotating said tube and die members, one of said die members being rotated.

8. In a device for forming substantially-parallel circumferential corrugations in a tube, inner and outer die members for cooperating with said tube, said tube and die members being in- 75 ternally tangential, said die members being of substantially the same radii as the internal and. external radii of the tube, and means for relatively rotating said tube and die members, said inner die member being rotatable.

9. In a device for forming circumferential corrugations in a tube, a plurality of die members for engaging one of the outer and inner surfaces of said tube, a cooperating die member engaging the other of said surfaces of said tube, means whereby said first-named die members may be actuated to vary the distance between them progressively, and means for relatively rotating said tube and die members, said inner die member being rotatable.

10. In a device for forming circumferential corrugations in a tube, a plurality of die members for engaging the outer surface of said tube, a cooperating die member engaging the inner surface of said tube, means whereby said first-named die members may be actuated to decrease the distance between them progressively, and means for relatively rotating said tube and die members, said inner die member being rotatable. I

11. In a device for making a bellows by forming substantially-parallel corrugations in a thin walled tube, inner and outer die members cooperating with said tube, and means for positively rotating one of said die members and thereby drawing said tube frictionally between said die members, one of said inner and outer die members having a circumferentially elongated arcuate contact with said tube.

12. In a device for making a bellows by forming substantially-parallel corrugations in a thinwalled tube, inner and outer die members cooperating with said tube, and means for positively rotating one of said die members and thereby drawing said tube frictionally between said die members, said outer die member having a circumferentially elongated arcuate contact with said tube.

13. In a device for making a bellows by forming substantially-parallel corrugations in a thinwalled tube, an inner rotatable die cooperating with said tube, an outer stationary die cooperating with said tube, and means for rotating said inner die and thereby frictionally drawing said tube between said dies, one of said dies having a circumferentially elongated arcuate contact with said tube.

14. In a device for making a bellows by forming substantially-parallel corrugations in a thinwalled tube, an inner rotatable die cooperating with said tube, an outer stationary die cooperating with said tube, and means for rotating said inner die and thereby frictionally drawing said tube between said dies, said outer die having a circumferentially elongated arcuate contact with said tube.

15. The method of making a bellows which includes frictionally rotating a thin-walled tube between inner and outer die members While positively driving one of said die members to rotate said tube and displacing a portion of said tube radially by simultaneous elongated arcuate contact with the other of said die members to form circumferentially' closed corrugations.

16. The method of making a bellows which includes frictionally rotating a thin-walled tube between inner and outer die members while positively driving said inner die member to rotate said tube and displacing a portion of said tube radially by simultaneous elongated arcuate contact with the exterior of said tube to form circumferentially-closed corrugations.

17. The method of making a bellows which includes rotating a thin-walled tube between and relatively to inner and outer die members by rotating the inner die member in frictional contact with said tube and displacing said tube radially between said die members to form circumferentially closed corrugations by making elongated arcuate contact with the outer circumference of said tube by one of said die members.

EDGAR C. STANLEY. 

